Optical projection apparatus.



No. 782,586. PATENTED FEB. 14, 1905.

- A. T. THOMPSON.

OPTICAL PROJECTION APPARATUS. APPLICATION rrnsn NOV. 21, 1904.

8 BHEBTSBHBET 1.

No. 782,586. A PATENTED PEB.14,1905.

A. T.'THOMPSON.

OPTICAL PROJECTION APPARATUS. APPLICATION FILED NOV. 21, 1904.

3 SHEETS-SHEET 2.

U/z'zfnessea: Inventor: @Ma/L W (I $11M @M/ y @M Q WM No. 782,586.PATENTED FEB; 14; 1905.

A. T. THOMPSON.

OPTICAL PROJECTION APPARATUS.

'APPLIUATION FILED NOV. 21, 1904. I

s SHEETQ-SHEET a.

, slide projection devices or the analogue thereof adapted foruse inconnectionwith trans-1.

* V UNITED STATES Patented February 14, 1905.

PATENT OFFICE.

ALBERT T. THOMPSON, OF BOSTON, MASSACHUSETTS.

OPTICAL PROJECTION APPARATUS- SPECIFIGATION forming part of LettersPatent No. 782,586, dated February 14, 1905. I Application filedNovember 21, 1904. Serial No. 233,610.

Ton/U whmn it may concern:

Be it known that I, ALBERT T. THOMPSON, a

citizen of the United States, residing at Boston, in the county ofSuffolk, State of Massachusetts, have invented a certain new and usefulImprovement in Optical Projection'Appa ratus, of which the following isa specification, reference being had therein to the accompanyingdrawings.

Theinvention consists in general in an apparatus of improved and novelconstruction which is adapted to be employed both for parent opticalsubjects or material and which devices may be of usual or approvedcharaoter for the purpose, the said devices embracing, essentially, a lightingmeans, such as an electric or other lamp or a mirror for reflectingsolar light, a condenser-lens, a slide-stage, a slide-carrier, or ananalogous stage and carrier, and an objective-lens, which last may betermed hereinafter the main objective-lens; also, one or more holdersfor the photographs or other opaque optical subjects or material fromwhich reflected images are to be projected, with a secondaryobjective-lens for the 1 projection of such images and in the morecomplete embodiment of the invention with a mirrorreceiving the imagefrom the secondmain objective-lens.

from a lantern-slide.

movably in a location intermediate the condenser-lens and mainobjective-lens.

In the inoperative position of the holder or holders it or they is orare retracted from the path of the beam of light which passes from thecondenser-lens to the main objective-lens. When the holder or holdersis' or are thus retracted, the apparatus may be employed in the mannerin which it is customary to employ apparatus for projecting from slidesor analogous transparent optical material. When the apparatus is to beused for the production of reflected images from opaque Objects-theslide-carrier or the like is removed and the holder or one thereof isplaced 'in its operative position, the picture or other object suptionas the image which is projected by the s The apparatus is adapted toproject images from transparent optical material and opaque opticalmaterial in alternating succession in any desired order forward toward ascreen in front of the apparatus and when the reflecting-mirror isemployed arranged as just stated'without it being necessary tocompletelyreverse or rotate the latter when the change is made from the one kindof projection to the other. When it is not desired to provide'for'lantern-slide projection, the main objective-lens, the stage,

and the slide-carrier may be omitted.

I have illustrated an embodiment of the invention in the drawings, inwhich I Figure 1 is a side elevation of'an optical projection apparatuscontaining the said embodiment, the said apparatus as represented inthis figure being in readiness for projection Fig. 2 is a View inhorizontal section on the dottedline 2 2 of Fig. Fig. 3, Sheet :2, is anelevation of the apparatus, viewing the side of the latter which isopposite that shown in Fig.1. Fig. 4, Sheet 2, is a view similar to Fig.1, showing the ap paratus in readiness for projection from a photographor other opaque optical material. Fig. 5, Sheet 3, is a view inhorizontal section on the plane indicated by the dotted line 5 5 in Fig.4. Fig.6, Sheet 3, shows inplan the apparatus arranged as in Fig. 4.

In the drawings, at 1 is represented a compound condenser-lens orcondenser-lens system, and at 2 is a compound objective-lens orobjective-lensfsystem.

At 50 50 are shown the carbons of an electric-arc lamp, the said carbonsbeing disposed at right angles to each other, with one of the saidcarbons extending lengthwise in the line of the axis of thecondenser-lens. The form of electric-arc lamp in which the carbons arethus arranged is well known in the market. Any otherlamp suitable forthe purpose, electric or otherwise, may be employed in practice, or aburner of a suitable character, or a mirror disposed-at a suitable angleto reflect solar rays through the condenser-lens may in some instancesbe utilized in the place of a lamp. For convenience of designation Icomprehend any one of these various means under the term source ofillumination.

Supporting-stands are shown at 3 and 4. With the first-mentioned onethereof the condenser-lens 1 and certain adjacent parts are connected;with the other thereof the objective-lens 2 is connected. The stand 3also has attached thereto the casing 5, which latter incloses portion ofthe condenser-lens system, as indicated by Figs. 2 and 5. Within thecasing 5 is provided a slide-stage at 6, Figs. 2 and 5, the latterhaving in connection therewith opposite 1%guides, as at 61 61, betweenwhich may be slid for lantern-slide projection the slide-carrier 7,Figs. 1 and 2, and the lensholder 8, supporting the supplementarycondenser-lens 9. To provide for the insertion of these latter partsinto operative position within the casing 5, an opening is formed in oneside wall of the latter, a movable door 10 being provided for the saidopening, the door 10 being hinged at 100 100, Fig. 4, to the adjoiningportion of the said side wall to enable it to be swung into an open orclosed position, as desired.

Figs. 1 and 2 show the door swung open, with the slide-carrier 7,lens-holder 8, and lens 9 inserted into position for lantern-slideprojection. The remaining figures show the slidecarrier 7, lens-holder8, and lens 9 removed and the door 10 closed, as required in making useof the apparatus in projecting from opaque optical material such, forinstance, as a photograph. Lens-holder 8 is furnished at its outer endwith a plate 81, Figs. 1 and 2, which serves to close the opening in thecasing at the said end of the lens-holder. The forward portion of thecasing 5 adjacent the objective-lens systems.

is formed with an opening 52, as indicated in Fig. 2, to permit the beamof light to pass on its way from the condenser-lens to theobjective-lens. Provision is made, as usual in optical projectionlanterns, for varying the distance which separates the condenser-lensand objective-lens from each other, as necessary in focusing forlantern-slide projection. Thus stand 4 has connected therewith a pair ofhorizontal .rods 11 11, the said rods, respectively, being located atopposite sides of the two lens The rods 11 11 telescope into tubes 1212, which latter pass through tubular guides 13 13, which are attachedto the stand 3. Clamping-screws 14 15, applied, respectively, to thetubes 12 and guides 13, secure the rods and tubes fixedly together afterthe stands 3' and 4 have been adjusted to the proper distance from eachother.

As thus far described the parts which are employed in lantern-slideprojection act essentially as heretofore. The precise construction, &c.,is not material to the present invention.

Two holders for photographs or other articles from which reflectedimages are to be projected are represented at l6 17. The said holdersare movable into and out of working position. In the working position ofa holder it extends across the opening 52 of the casing 5, as in thecase of the holder 17 in Fig. 5. In this position it intersects at anangle the path of the beam of light on the way from the condenser-lens.When a holder is moved out of working position, it is caused to occupy aposition at one side of the path of the'said beam, as indicated in thecase of the holder 16 in Figs. 2, 5, and 6 and of the holder 17 in Fig.2. The number of the holders, as well as the manner of supporting theholder or holders and providing for the movement of the same into andout of the working position thereof, may vary in practice. In thepresent instance I have shown two holders, which are hinged,respectively, at 161 161 and 171 171 to the casing 5 at opposite sidesof the opening 52. As shown in Fig. 2, both holders may be swung backinto inoperative positions at the same time to enable the apparatus tobe used for lantern-slide projection or the like, or in projecting theimages of opaque objects first one holder may be swung into operative orworking position, as in the case of the holder 17 of Fig. 5, and thenthe other. The purpose of employing a plurality of holders is to enablea quick change to be effected it intersects the path of the beam oflight at an angle or forty-five degrees. The secondary objective-lens orobjective-lens system is shown at 18. It coacts with the holder which isin working position and serves to project the image of the picture orother article or object which is attached o.- applied to the saidholder. The said secondary objective-lens is applied to an opening in aside wall of the casing 5 opposite and in line with the opening 52. Theaxis of the said secondary objective-lens extends at right angles to theplane of the object-holder which occupies its operative position. (SeeFig. 5.) Ata suitable distance to the exterior of the secondaryobjective-lens 18 is located the mirror 19; This mirror may be omitted,if desired; but in such case in order to throw the images from therespective object-lenses 2 and 18 alternately upon the same screen itwill be necessary to reverse the position of the apparatus by com.-municating approximately a half rotation thereto at the time of makingeach change from one kind of projection to the other.

The-mirror 19 enables the images from thesecondary objective-lensto bethrown forward in practically the same direction as the' image from themain objective-lens. It usually is set ata slight angle relative to theaxis of the secondary objective-lens in order that the reflection fromthe mirror may clear the outer end of the casing of the lens.- Thisinclination is comparatively slight, and hence in order to enable theimages which are produced by the two different modes of projection to bethrown upon one and the same screen it is necessary simply to swing theapparatus very slightly in changing from lantern-slide proection toopaque-object pro ection, and vice versa.

ondary objective-lens.

For the support of the mirror it is furnished with a stem 192, whichpasses through a socket 191 in the outer end of an arm 20, extendinghorizontally from the easing 5. The inner end of said arm passes througha socket 21 upon the said casing. By means of the clamping-screws 22 23,applied to the sockets 191 and 21, respectively, the parts may besecured fixedly in the desired positions. Socket 191, stem 192,andclamping-screw 22 enable the mirror to be set at any desired heightwith respect to the see- It also enables the mirror to be set at thedesired obliquity or inclination in a vertical plane in order to enablethe image to be thrown at the requiredangle. Socket 2 1, arm 20,and'clamping-screw 23 enable themirror to be adjusted-toward and fromthe secondary objective-lens. When the image of printed matter isrequired to be projected, the mirror 19 operates to reverse the image,so as to cause the words to extend in the proper direction for; beingread.

While I have beenmore or less particular iii-describing the illustratedembodiment'off the invention, yet it-is to be understood that theprecise construction and arrangement herein shown and described are notinall respects of the gist of the invention in the broader phases of thelatter.

I claim as my invention 7 1. An optical projection apparatus com prismg,m combination, a condenser-lens. a slidestage, a main objective-lens, anobject-holder movable into and out of a position intermediate the saidcondenser-lens and ob ectivelens in which it intersects the path of therays passing from the former toward the latter,

and a secondary objective-lens coacting with the object-holder when thelatter occupies its operative position intersecting the said path.

2. An optical projection apparatus comprising, in combination, acondenser-lens, a slidestage, a main objective-lens, an object-holdermovable into and out of a position intermediate the said condenser-lensand objectivelens in which it intersects the path of the rays passingfrom the former-toward the latter, a secondary objective-lens coactingwith the object-holder when the latter occupies its operative positionintersecting the said path, and a reflector receiving the image of theobject on said object-holder from the said secondary objective-lens. 1

' 3. In an optical projection apparatus, in combination, a source ofillumination, a condenser-lens, an object-holder'having a workingposition in whichit intersects at an angle to the path of the beam ofrays from the condenser-lens, an objective-lens having its axis at rightangles tothe said working position of the object-holder and coactipgtherewith, and a reflector receiving the image from the saidobjective-lens and'throwing the same directly onto the screen. P

4. In an optical projection apparatus, in combination, acondenser-lens,object-holders respectively located atopposite sides ofthe path of the beam of raysfrom the said condenserlens and alternatelymovable into a working position'intersecting the said path, and anobjective-lens coacting with the said object-holders when thelatterrespectively are in the said working position. I

5. In an optical projection apparatus, in combi nation,"a condenserdens,object-holders pivotally mountedat opposite sides of the path of thebeam of raysfrom the said condenser-lens and alternately movable into aworking position intersecting the said path, and anobjective-lens'coaeting with the said object-holders when thelatter-respectively are in the said workingpositibn.

6. An optical projeetionapparatus comprising, in combination, acondenser-lens, a slidestage, a main objective-lens, object-holdersrespectively located at opposite sides of the path of the beam ofraysfrom'the said condenserlens and alternately movable into a workingposition intersecting the said path intermediate, the'condenser-lensandthe main objeclive-lens, and a secondary objective-lens coacting withthe said object-holders when the latter respectively are in the saidworking position.

7 An optical projection apparatus comprising, in combination, acondenser-lens, a slideslage, a main ob jective-lens, object-holdersrespectively located at opposite sides of the path of the beam of raysfrom the said condenser- 1 lens and alternately movable into a workingposition intersecting the' said path intermediate the condenser-lens andthe main objec with the said object-holders when the latter respectivelyare in the said working position,

and a reflector receiving from the said secondary lens the image of theobject on the object-holder which is in the working position. Intestimony whereof I aflix my signature in presence of two witnesses.

v ALBERT T. THOMPSON. Witnesses:

CHAS. F. RANDALL, EDITH J. ANDERSON.

